1. Field of the Present Disclosure
This disclosure relates generally to insulating methods for tanks and especially hot water heater tanks, and more particularly to a fabric based system for such applications wherein dead air spaces are established as a primary insulating feature.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Giamati, U.S. 2003/0210902, discloses a heater for installation on a potable water tank. The heater comprises a blanket including an electrical resistance heating element and a connection pad for electrically connecting the heating element to lead lines to an aircraft power source. The water tank is typically positioned under the cabin floor or other locations on an aircraft which are susceptible to cold temperatures, moisture invasion, and pressure drops/rises caused by changing altitudes. The heater maintains the tank at an acceptable temperature range and prevents freezing of the water. Lohse, U.S. Pat. No. 1,240,462, discloses a heat insulating unit comprising a thin block of asbestos provided with projecting flanges, a metallic lath embedded within the block and extending therethrough from edge to edge, and heat insulting pins carried by the block and extending therefrom in a direction lateral to the general plane thereof. Gazelle, U.S. Pat. No. 1,737,712, discloses a water tank of the character described, comprising a main tank, an inlet and outlet pipe connected thereto, an intermediate tank enclosing the main tank and suitably distanced therefrom, means on the inner surface of the intermediate tank to reflect the heat rays radiating from the main tank, an insulating lining located between the bottoms of the tanks, a frame for supporting the tanks, an insulating lining located between the intermediate tank and the frame, and an outer open and superposed casing enclosing the intermediate tank, suitable distanced therefrom and supported upon the frame. Geyer, U.S. Pat. No. 1,912,834, discloses a combined instantaneous and storage water heater comprising, in combination, a storage tank having a vertical tube therein; a flue within and spaced from the tube; a coil of substantially uniform diameter within the flue and connected to the tank; a perforated burner tube extending through the flue and arranged to discharge jets against the coil throughout its height; means for removably supporting the burner tube in the flue; and a fuel supply pipe connected to the burner tube, the coil and burner tube being so arranged as to be removed through the upper end of the flue, a thermostatic element in the tank connected to control the supply of fuel to the burner tube. Mcferran, U.S. Pat. No. 2,642,851, discloses a water heater jacket, in assembly constituting a complete jacket for the walls and top of a water heater, and comprising two members of semi-cylindrical form each having a half-top member, each of the half-top members having half-openings for a vent pipe and fro water fittings, one of the semi-cylindrical members having an aperture for a control window, each member comprising an outer shell member and a lining of insulating material, the members along substantially, the entire length of their meeting side and top edges having cooperating joint forming elements, the joint forming element on one of the semi-cylindrical members comprising an inwardly offset flange, and the joint forming element on the other semi-cylindrical member comprising a flange along the inside of the shell member, spaced therefrom, extending beyond the edge thereof, and terminating ion an outwardly extending bead. Carson, U.S. Pat. No. 2,563,817, discloses a gas fired water heater, comprising a water storage tank having a vertical tube extending therethrough to provide an uptake passage for products of combustion, an outer heat insulating casing enclosing the tank and spaced therefrom along the sides and at the top of the tank to provide a passage for products of combustion over the top of the tank communicating with an annular downtake passage surrounding the tank, the downtake passage having an outlet in the lower portion of the casing for the products of combustion, a gas burner in proximity to the bottom of the tube, and a substantially cylindrical metallic member having its bottom end closed and supported by the top of the burner, the cylindrical member having spirally arranged fins on its outer surface to constitute a convection type heat transfer element in the lower portion of the tube, thereby increasing the transfer of heat by convection from the burned gasses through the tube wall to the water in the lower portion of the tank, the products of combustion thereafter passing upwardly through the tube and thence over the top of the tank and downwardly around the tank to the outlet, whereby the water is heated to a relatively uniform temperature throughout the tank. Mather et al., U.S. Pat. No. 3,358,118, discloses a water heater comprising, in combination, an inner cylindrical pressure tank having water inlet and outlet means, a generally cylindrical two-piece outer shell fully enclosing the pressure tank and adapted for ready dismantlement as to permit replacement of the pressure tank; a base supporting the tank and the shell, the heater including electric heating means, thermostat means for controlling the operation of the heating means, and insulation, the insulation being attached to the inside surface of the outer shell, and means for holding the heating means and thermostat means within the shell and in removable juxtaposition with the outer surface of the sides of the pressure tank, the holding means consisting of a standard carried by and projecting upwardly from the base within the shell and between the shell and the pressure tank, the standard being adjustable in height as to permit height adjustment of the heating means. Denton, U.S. Pat. No. 4,527,543, discloses a water heater including a tank, a cylindrical jacket, surrounding the tank to provide an insulating space therebetween and a cover member mounted on top of the jacket to close off the top of the insulating space. An insulating wall is provided in the insulating space between the tank and the jacket. The insulating wall is comprised of a plastic envelope member and a wall of insulating material which has been foamed-in-place inside the envelope member. Nelson, U.S. Pat. No. 5,020,481, discloses a thermal insulating jacket for use around pipes, conduits, tanks and related members that includes a flexible outer covering such as a sheet of plastic or polyvinylchloride which has bonded to its surface an alternating series of insulation material strips. The insulation material strips which are bonded to the flexible outer covering include a first plurality of flexible insulation material strips and a second plurality of rigid insulation material strips. These different material strips are arranged in alternating sequence and the combination of outer covering and insulation strips is sufficiently flexible and formable so as to be wrapped into a generally cylindrical shape which may then be disposed around a pipe, conduit, tank or related member, for thermally insulating that member. The outer covering may be a one-piece member or a hinged member. Nelson, U.S. Pat. No. 5,024,210, discloses a water heater for containing water surrounded in spaced apart relationship by an outer shell that includes a sleeve of insulation material, such as fiberglass, located in the annular space between the inner tank and outer sleeve. The top edge of the insulation sleeve includes an annular cuff which is of a radial thickness greater than the radial thickness of the rest of the insulation sleeve such that the cuff is compressed between the interior wall surface of the outer shell and exterior wall surface of the inner tank. An expanded foam thermal insulation material fills the annular space above the cuff of the insulation mat. A method of making a water heater includes the steps of locating a sleeve of insulation material around the exterior wall surface of the inner tank, folding the top end of the insulation sleeve back over itself to form an annular cuff, and positioning the outer shell concentrically over the inner tank whereupon the annular cuff is compressed between the interior wall surface of the outer shell and exterior wall surface of the inner tank. The annular space above the annular cuff of the sleeve is then filled with an expandable foam insulation material which is allowed to foam in situ. Hickman, U.S. Pat. No. 5,213,728, discloses a method for foam insulating a water heater where the water heater has an outer shell and an inner tank with tank fittings, the outer shell having tank fitting openings and the inner tank and outer shell being separated by an insulation space. The method comprises locating foam flow barriers between the inner tank and the outer shell around the periphery of each of the tank fitting openings and then spraying foam forming material into the insulation space with the foam barriers preventing the foam from escaping outwardly through the tank fitting openings. Hickman, U.S. Pat. No. 5,263,469, discloses a method for foam insulating a water heater where the water heater has an outer shell and an inner tank with tank fittings, the outer shell having tank fitting openings and the inner tank and outer shell being separated by an insulation space. The method comprises locating foam flow barriers between the inner tank and the outer shell around the periphery of each of the tank fitting openings and then spraying foam forming material into the insulation space with the foam barriers preventing the foam from escaping outwardly through the tank fitting openings. Boffito et al., U.S. Pat. No. 5,408,832, discloses an improved process for evacuating the thermally insulating jacket of a dewar having an inner wall and an outer wall, with the inner space between said walls completely or partially filled with an insulating material, containing also a moisture sorbing material and a getter material, in which said moisture sorbing material is a chemical drying agent. Vessells et al., U.S. Pat. No. 5,921,230, discloses an insulating mechanism for a gas water heater designed to increase the efficiency thereof. The device comprises a blanket formed of a pair of arcuate, adjacent panel members having top and bottom edges with a pair of opposing side edges therebetween. Adjacent side edges of the panel members are hingedly joined with the opposing side edges being selectively attachable to form a cylindrical blanket that encases a water heater storage reservoir. A piping system is disposed within each panel member for circulating waste gas therethrough. An exhaust duct is disposed on the top surface of a water heater outer shell and is in communication with the interior thereof. A hinged baffle divides the duct into an upper and lower chamber both of which are in communication with the piping system. A fan is disposed within the lower chamber and forces hot waste gas from within the outer shell through the blanket and out the top of the duct thereby providing a heated, insulating blanket for the water storage reservoir. Lewis, U.S. Pat. No. 5,979,371, discloses a foam distribution jacket for containing an insulating expandable liquid foam mixture prior to expansion into a space between a hot water tank and an outer casing secured thereabout. The jacket comprises a pair of sheets which are superimposed to define a bottom trough section having a straight bottom edge and opposed end edges. A seal is formed along the straight bottom edge and the opposed end edges to form the trough and to interconnect the sheets. The pair of sheets converge to a crest portion at a top end section thereof. An attachment hole is provided in the crest of an inner one of the pair of sheets) and is adapted to attach the jacket in a depending manner from a nipple in a top wall of a hot water tank. The method of insulating a surrounding space formed between the hot water tank and the outer casing using the foam distribution jacket is also described. Kingston, U.S. Pat. No. 6,412,448, discloses a flexible, water impervious liner that is fitted in a rigid outer shell. The shell has an open top with a peripheral flange over which a top lip of the liner is fitted. A separate top plate attaches to the flange with standard fasteners for clamping the liner to the shell. Through hull fittings are provided for heating elements at the side and inlet/outlet fittings at the top. The construction allows convenient access to virtually all components of the water heater, including the liner and the heating elements, so that they can be quickly and easily serviced or replaced. A desired amount of insulation can be provided by an appropriate cover or blanket to surround the outer shell. Lieske, U.S. Pat. No. 6,595,431, discloses a exhaust heat trap and redirecting system for utilizing exhaust heat that includes an electric generator that includes an internal combustion engine. The electric generator is electrically coupled to an electrical system of a dwelling. An exhaust conduit is fluidly coupled to the engine for venting exhaust away therefrom. A substantially airtight sheath is positioned about a water tank in a water heater. The sheath comprises a cylinder having an inner wall and an outer wall. The sheath has an upper wall attached to the outer wall. A sheath inlet has a first end fluidly coupled to the sheath and a second end fluidly coupled to the exhaust conduit. A sheath outlet has a first end fluidly coupled to the upper wall of the sheath and a second end is directed outward of the dwelling. Shigemi, JP 6229504, discloses a casing structure for a furnace wall of a boiler wherein even if a boiler is started and stopped frequently, exhaust gas of high temperature does not directly contact a metal plate or an expansion plate so that the metal plate and expansion plate can be kept at a low temperature. The casing structure of the furnace all of a boiler, the end of a water-tube furnace wall and the end of a steam-tube furnace wall are positioned at right angles spaced apart a vertical gap from each other and a L-shaped metal plate having a plurality of horizontal gaps and an expansion plate of U-shape are provided so as to surround the vertical gap. And one of the surfaces of the plate extends along the wall and the other surface thereof extends along the wall and the opposite ends thereof in a horizontal direction are joined to the water-tube furnace wall and the steam-tube furnace wall, and the upper and lower ends of the expansion plate are joined to the L-shaped metal plate so as to hold a horizontal gap therebetween. Further the flexible insulating material is filled into between the walls and the metal place and also is filled into the interior of the plate. Vallis, GB 2365102, discloses a water heater comprising a lower reservoir for heated water and an upper cold water feed/expansion reservoir which are interconnected by a cold water supply pipe and a hot water expansion pipe, the expansion pipe is insulated from the water in the cold water reservoir. This prevents heat from the expansion pipe warming up the cold water in the reservoir sufficiently to allow harmful bacteria to develop. The expansion pipe may be insulated by means of a sleeve of thermally insulting material surrounding and in contact with the pipe. Alternatively, the sleeve is of copper and surrounds the pipe with an air gap. The end of the pipe has a U-bend. The reservoirs are separated by an air gap or by thermally insulating material and pipes are made of material which is resistant to the flow of heat through it or fastened by insulated collars. The cold water reservoir has a temperature sensor which generates an alarm signal if the temperature exceeds 39° C. This educes the risk of bacterial growth which can cause legionnaires disease. The alarm signal may produce an audible and/or visible alarm, either immediately or after a predetermined time, or may activate a valve to prevent flow from the water heater. Alternatively the temperature sensor may just change color, or from transparent to opaque, to indicated to a service engineer that the temperature has been exceeded since the last visit.
The related art described above discloses a variety of approaches to providing thermal insulation to a tank. For instance, McFerran, Giamati, GB 2365102, Buffito et al, Kingston, Hickman, Nelson, Denton and Mather at al, all teach that insulation material is best when in contact with the tank to be insulated. In contrast, Lieske, Carson, Gazelle, Lohse and Geyer all teach placement of rigid walls leaving a dead air space between the wall and the tank. For instance, Geyer uses sheet metal, Hohse uses asbestos in a metallic lath, Gazelle uses galvanized tin, Carson teaches an insulating material between sheet metal walls, and Lieske teaches rigid walls with passages for hot air to pass. However, the prior art fails to disclose an apparatus made of a multi-layer flexible fabric with integral spacers for establishing dead air spaces between the fabric and the tank. Such materials are less expensive to manufacture, ship, store and employ due to the fact that they can be folded compactly, are light weight and simple to assemble and install. The present disclosure distinguishes over the prior art providing heretofore unknown advantages as described in the following summary.